New paper out! Micronutrients enhance macronutrient effects in a meta-analysis of grassland arthropod abundance

A meta-analysis led my myself, Karen Castillioni, and Ellen Welti is now out in Global Ecology and Biogeography! This paper examined the effects of micro- and macronutrient fertilization in grasslands on plant biomass, plant nutrient content, and on the abundance of six arthropod trophic groups.

We found the interesting result that micronutrients applied alone had no effects on plant biomass or arthropod abundance. However, when added with macronutrients (such as nitrogen, phosphorus, and potassium), micronutrients amplified the effect of N, P and K in promoting arthropod abundance, a synergy that did not affect plant biomass (Figure 1).

Figure 2. Forest plot showing effect sizes (Cohen’s d) of (a) plant biomass and (b) total arthropod abundances by fertilizer type. Red stars denote significant effect sizes, while black circles indicate non-significant effect sizes. We included fertilizer types used in > 5 studies. The number of replicates provided within the figure refers to the number of experimental responses containing each fertilizer type. Error bars are the standard error of the mean of the effect sizes of individual experiments

Micronutrients catalyzed the ability of macronutrients to promote arthropod abundance across all arthropod guilds studied (Figure 2).

Figure 2. Forest plot showing effect sizes (Cohen’s d) of arthropod trophic group abundances by fertilizer type. Responses are provided for the trophic groups of (a) chewing herbivores, (b) sucking herbivores, (c) pollinators, (d) omnivores, (e) predators, and (f) detritivores. Red stars denote significant effect sizes, while black circles indicate non-significant effect sizes. We included fertilizer types used in ≥ 5 studies. Number of replicates provided within the figure refers to the number of experimental responses containing each fertilizer type and trophic group. Error bars are the standard error of the mean of the effect sizes of individual experiments

This paper was a result of a collaboration with Dr. Lara Souza and Dr. Mike Kaspari at OU and Dr. Chelse Prather and Ryan Reihart at the University of Dayton. We highlight a stoichiometric mismatch between limits of plants and arthropods for metal cations whose biogeochemistry, along with N and P, are being actively rearranged in the Anthropocene.

You can read the paper here. https://rmprather.files.wordpress.com/2020/10/prather-et-al.-2020-geb-meta-analysis.pdf

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